1. Field Of The Invention
This invention relates to an automatic opening and closing device for a window, and in particular to motor driven automatic opening and closing device for a window which is suitable for opening and closing a window and which is also called a power window in the case of use for an automobile.
2.Description of the Prior Art
Two types of opening and closing devices for a window of an automobile are known. One of them is a type which is wound-up and wound-down by manual operation, and another type is a power window herein the window is activated up and down automatically by a drive motor with a switching operation. Among them, the latter has been popularized recently, because it is possible that the window can be opened or closed only by a switching operation while driving the automobile. The automatic opening and closing device for the window is, generally, a device wherein the window is moved to be opened or closed by activating the forwardly and reversely rotatable motor with a manual operation switch. The window continues to ascend or descend while the manual operation switch is switched on.
Meanwhile, in the case of smoking in a car compartment, air in the car compartment is tainted, so that the window is sometimes opened sufficiently to accelerate ventilation of air. In this case, it is necessary to operate an up-down-switch delicately. Therefore, if the driver performs such a switching operation while driving the car, the driving operation is disturbed, so that there is the possibility of causing an accident.
To prevent the above mentioned problem accompanied by the operation for opening and closing the window, for example, there is a device disclosed in Japanese Utility Model Publication No. 60-169015. Considering the fact that a smoker uses an ashtray during smoking, the device is designed such that drawing the ashtray from a retainer of a smoking fixture provided in the car compartment, the window begins to open in linkage with it, and stops automatically when the window is opened a predetermined amount so desirable ventilation is obtained.
However, in the device described in said Publication, the cost of the parts and assembling increases because it is necessary to additionally provide a switching means for the machinery for ascent and descent related to the smoking fixture in order to open and close the window. Furthermore, it is necessary to draw the ashtray for the ventilation even if tobacco is not smoked.
On the other hand, in the automatic opening and closing device for the window, there is a problem that if an obstacle such as a hand or a head of an occupant is inserted between the window and a window frame in the ascending process of the window, the obstacle is caught between them. Therefore, various methods have been examined to resolve the problem.
For example, Japanese Patent Publication No. 60-185626 discloses a method wherein an abnormality such as squeezing of the obstacle is detected by means of detecting the bending of an optical fiber assembled into the window frame. Further, Japanese Patent Publication No. 60-185625 discloses a method wherein a pattern of electric charging data of a motor for ascending and descending the window under the normal state is memorized previously and an abnormality such as squeezing of the obstacle is detected by comparing said data as a reference pattern with data at actual operation.
However, concerning the method described in said Patent Publication No. 60-185626 it is necessary to assemble an expensive optical fiber into the window frame, working steps increase and a special detecting device must be provided In general, on the occasion of mounting a sensor for squeezing detection it is the present situation that a practical application is difficult for the problem in mounting due to limitations in manufacturing of the door part including the window frame and the window and a substantial increase in cost following this and a problem in reliability.
With respect to the method described in Patent Publication No. 60-185625, although the influence of fluctuations of motor load including a slide resistance between the window and the wind frame mounted on the car can be solved, it is necessary to operate the manual memory-switch for memorizing the reference data when the window is ascended or descended. Further, it is necessary to provide a limit switch for detecting whether the window gets to the full-opened position or full-closed position. Furthermore, there is no consideration concerning the fact that the reference data is the data under normal operation.